A New York City police officer watches as movie patrons arrive Friday for a screening of "The Dark Knight Rises" in New York. A gunman in a gas mask barged into a crowded Denver-area theater during a midnight premiere of the Batman movie on Friday, hurled a gas canister and then opened fire, killing 12 people and injuring at least 50 others in one of the deadliest mass shootings in recent U.S. history. NYPD commissioner Ray Kelly said the department was providing the extra security at theaters "as a precaution against copycats and to raise the comfort levels among movie patrons." (ASSOCIATED PRESS / Mark Lennihan)

New York police posted officers at dozens of theaters around the city. Ticket-takers at a multiplex in Washington searched moviegoers’ bags and purses. And one of the nation’s biggest theater chains barred patrons from wearing masks or costumes.

Security was stepped up in places around the U.S. during showings of the new Batman movie Friday after the massacre in Colorado. And while some people said they were afraid to go to the movies in the wake of the shooting rampage, many others were undeterred by the tragedy and eager to see “The Dark Knight Rises.”

Jimmy Baker, 40, waited outside the AMC theater in New York’s Time Square for almost three hours to see an early matinee, as a police cruiser sat nearby.

“I just felt bad for the people that had to be traumatized by this entire event,” he said. But “I didn’t feel like it had any kind of effect on me. ... I’m just here to enjoy a good movie.”

Stephanie Suriel, 21, waiting outside the same theater, said her mother was slightly concerned about her going to see the film. But “I’m not nervous at all because I really want to see that movie.”

Still, just to be safe, she said, “I’m going to sit in the back.”

Theaters took the precautions after a gunman wearing a gas mask opened fire at a midnight showing of “The Dark Knight Rises” in Aurora, Colo., killing at least 12 people. There was extra security Friday night at four theaters showing the movie in Aurora, Police Chief Dan Oates said.

In Washington, the Homeland Security Department held a conference call with officials from the commercial, entertainment and shopping mall industries to discuss what security measures they could take to prevent something like this from happening again.

The National Association of Theater Owners said it was working closely with law enforcement authorities and reviewing security procedures, but gave no details of any precautions taken.

AMC Theatres, the nation’s second-largest theater chain, with more than 300 movie houses, said it will not allow people to wear costumes or face-covering masks into its theaters.

Fans of sci-fi and superhero movies often dress up as their favorite characters, especially on opening night. New York City’s police commissioner said the gunman in the Colorado rampage painted his hair red and called himself the Joker, Batman’s nemesis. But Aurora police would not confirm that.

The New York Police Department said was posting officers at about 40 theaters around the city that were showing the film. The increased security was a precaution against potential copycat shooters, and also meant to reassure moviegoers.

At Landmark Theaters in Baltimore, moviegoer Kelly Hager said a 5 p.m. showing was nearly full with no sense of a somber mood among fellow patrons. She and a friend bought tickets earlier this week and never considered not going.

She said a few police officers were stationed outside but she saw none inside. After the movie, staff members stood outside and thanked people for coming.

“I guess they were worried that people would stay home,” said Hager, 32, of Baltimore, a TV station web producer. “I’ve never seen that happen before.”

At the Regal Gallery Place multiplex in downtown Washington, moviegoers trickled into an 11 a.m. showing. Theater employees searched patrons’ bags and purses while taking their tickets.

“I’m believing that it’s not related so much to the movie,” Steve Glaude, a 57-year-old federal employee, said of the shooting. “The movie may have been a trigger. It may not have been. We don’t know. I don’t think it was hero or villain emulation.”

Christine Cooley, who works near Tampa, Fla., for the University of Florida, said her 15-year-old daughter has sworn off going to the movies because of the tragedy.

“It’s tainted the movie completely for her,” Cooley said. “It’s summertime. That’s a big movie time for teenagers. That movie is off the list now. Movie theaters in general are off her summer to-do list because of that.”

Cooley said she tried to explain that the shooting was random and not an indication of security at theaters in general, “but I can see where she’s coming from. Why put yourself in harm’s way?”

At the United Artists Riverview Stadium 17 in Philadelphia, a steady stream of people headed in for morning showings of “The Dark Knight Rises.” Staff members said that there was extra security, but that that was normal for big movies and unrelated to the Colorado shooting.